In modern high volume package delivery systems, package delivery services utilize a variety of material handling systems. Such material handling systems often include package conveying systems that divert packages to a variety of output destinations such as chutes, bins, and conveyor systems.
One of the most conventional types of conveyors is a belt conveyor, which includes the use of an endless flexible belt which passes over at least two cylindrical rollers, one of which is a drive roller. Packages are placed atop the upwardly-directed "working" surface of the belt conveyor, and are transported in a generally straight direction from end of the conveyor to the other. Another type of conveyor is a "roller" conveyor which con include powered or idling rollers which contact, support, and in certain instances propel the bottom of the package along its path.
Systems for diverting objects from a moving conveyor have been available for many years. Such systems are useful in discharging objects from a conveying surface at selected stations located along the path of the conveying surface.
Some package diverting systems utilize a pusher element or member mounted on or beneath a conveying surface which when actuated ejects a package laterally across the conveying surface to a desired discharge station. Many such systems guide a pusher element laterally across the conveying surface using a complex series of guide tracks, or elements mounted beneath the conveying surface. Other systems utilize a means for elevating and tilting a package above and away from the upper surface of a conveying surface so that the package may be withdrawn to an awaiting chute or discharge station. Still other systems have been known to collapse the conveying surface such that the package falls to a subjacent conveying surface on which the package is translated to a desired discharge location.
U.S. Pat. No. 1,462,511 discloses another conveyor diverter. A side conveyor extends perpendicular from a main conveyor. A set of diverting rollers are configured perpendicular to the main conveyor and are raised above the upper surface of the main conveyor to cause an object to be diverted from the surface of the main conveyor under force of gravity across the set of diverting rollers.
U.S. Pat. No. 1,549,499 discloses an elevating means for use in connection with roller bed sorting tables for raising a box or parcel a slight distance above the plane of the roller bed to allow the box or parcel to be withdrawn to an awaiting chute or discharge station. A box or parcel to be discharged is brought to a state of rest at a sorting station immediately above an elevating roller. The elevating roller is raised by depressing a foot lever. The box or parcel positioned over the elevating roller is raised off the roller bed which allows an operator to pull the box or parcel off the roller bed on to an adjacent chute or discharge station.
A box or parcel switching unit for discharging a box sideways on to an adjacent storage conveyor or chute is disclosed in U.S. Pat. No. 2,062,604. A box or parcel is brought to a stopped position on a receiving conveyor and overlying a discharge conveyor. The receiving conveyor is dropped from beneath the box or parcel allowing it to come to rest on the discharge conveyor. The box or parcel is then translated off the surface of the discharge conveyor to an awaiting adjacent conveyor or chute.
U.S. Pat. No. 3,138,238 discloses a conveyor system with a powered diverter for diverting an object from the surface of a main conveyor to an awaiting side conveyor. The powered diverter includes an assembly of diverting wheels that are oriented toward the side conveyor. The group of diverting wheels are normally positioned below the upper surface of the main conveyor so that objects traveling on the main conveyor do not contact the diverting wheels. In order to divert an object from the main conveyor to the side conveyor, the diverting wheels are elevated so that they are slightly above the upper surface of the main conveyor. Accordingly, an object traveling down the main conveyor is diverted by contact with the elevated diverting rollers.
U.S. Pat. No. 3,291,279 to DeGood likewise discloses a conveyor system with a powered diverter, which as shown in FIG. 8 works in conjunction with a shifting linkage 200. Chains of powered roller elements are used, which are indexed upwardly to engage packages to eject them at an angle from the original conveying path.
U.S. Pat. No. 3,303,923 to Davis discloses a conveyor diverter mechanism which includes a number of relatively thin conveying belts 25, 26, and 27 which are indexed upwardly as shown in FIG. 2 to engage and withdraw a selected package.
U.S. Pat. No. 4,598,815 to Adama discloses a powered roller diverter which includes a single row of powered diverter rollers which can be selectively indexed upwardly to engage and eject a package on a belt conveyor path. The single row of diverter rollers is selectively indexed upwardly from within a transverse gap between the downstream roller of an upstream conveyor to the upstream roller of a downstream conveyor, such that the rollers engage and discharge a package sidewardly.
U.S. Pat. No. 4,730,718 to Fazio discloses a `bi-directional mechanism" which, as shown well in FIG. 1, shows a plurality of elastomeric belts 76 mounted upon an indexable table assembly associated with a conveyor assembly. The belts are supported by indexable rollers such that portions of the belts can be indexed upwardly within elongate slots defined between elongate conveyor rollers being part of the conveyor assembly, to cause the belt portions to engage packages otherwise atop the conveyor rollers, and to eject them to either side of the conveyor path. The Kloosterhouse patent (U.S. Pat. No. 4,962,841), owned by the same assignee, likewise discloses such a configuration.
U.S. Pat. No. 4,979,606 to Usui discloses a transporting direction controlling device applicable to conveyor systems. As shown in FIGS. 1-5 of the Usui patent, the device utilizes a rotor member comprised substantially of a cylindrical or disk-shaped roller which is tiltable in variable directions for tilting the plane of the upper surface of the rotor member. By tilting the direction of the plane and the rotating direction of the rotor member, the transporting direction of a box or package may be changed. As shown in FIGS. 3(A)-3(D) of Usui, force is exerted on an object by tilting the plane of the rotating device so that the object will be moved in the direction tangent to the direction of travel of the upper most portion of the tilted rotating device. In practice, Usui describes using the rotating device in concert with a plurality of similar rotating devices to form a direction changing station, as shown in FIGS. 5 and 12. As shown in FIGS. 6 and 21, guide plates 116, 118, and 312 are used to define a direction change path for the object.
U.S. Pat. No. 5,165,516 to Reed discloses a three-way transfer conveyor which includes transfer belts which are selectively driven to the left and to the right at right angles to the conveyor rollers. As in the Fazio and Kloosterhouse references, the rubber belts fit into elongate transverse "gaps" between the conveyor rollers.
In some of those systems, diverter mechanisms are utilized to divert an object from the upper surface of a conveying surface by bringing the object to a complete stop overlying the diverter mechanism and then either raising the diverter mechanism or lowering the object so that the diverter mechanism comes into contact with the object. Bringing the object to a complete stop prior to being diverted causes a significant reduction in the efficiency and speed of operation of the conveyor system. Some of those systems move a diverter into the path of a moving object. Problems associated with those systems include the inability to eject objects laterally from the surface of a moving conveying system at ejection speeds which are independent of the speed of the moving conveyor system.
Other limitations in the prior art include an inability to eject objects laterally at a high speed without encountering rotation of the package or object as it is discharged from the surface of the moving conveyor. Furthermore, such systems may be noisy and relatively difficult to repair when diverter systems components fail.
Finally, some prior art systems are complex in construction and require substantial disassembly in order to replace the discharge elements should they wear out.
Thus, there is a need in the art for a sorting conveyor system that can discharge or eject an object from a conveying surface without bringing the object to a stop and without changing the position or speed of the conveying surface. There is also a need in the art for a sorting conveyor system that can discharge or eject an object from a conveying surface at high speeds and without undesired rotation of the object during discharge. There is further a need in the art for a sorting conveyor system that is quiet during operation and which is easily repaired. Finally, there is a need in the art for a conveying device which allow for quick changes of replacement parts in order to reduce downtime.